Caveolin-1 and -2 in the exocytic pathway of MDCK cells.
We have studied the biosynthesis and transport of the endogenous caveolins in MDCK cells. We show that in addition to homooligomers of caveolin-1, heterooligomeric complexes of caveolin-1 and -2 are formed in the ER. The oligomers become larger, increasingly detergent insoluble, and phosphorylated on caveolin-2 during transport to the cell surface. In the TGN caveolin-1/-2 heterooligomers are sorted into basolateral vesicles, whereas larger caveolin-1 homooligomers are targeted to the apical side. Caveolin-1 is present on both the apical and basolateral plasma membrane, whereas caveolin-2 is enriched on the basolateral surface where caveolae are present. This suggests that caveolin-1 and -2 heterooligomers are involved in caveolar biogenesis in the basolateral plasma membrane. Anti-caveolin-1 antibodies inhibit the apical delivery of influenza virus hemagglutinin without affecting basolateral transport of vesicular stomatitis virus G protein. Thus, we suggest that caveolin-1 homooligomers play a role in apical transport.
Scheiffele
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P
Cell Biology Programme, European Molecular Biology Laboratory, D-69012 Heidelberg, Germany.
Verkade
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Fra
A M
AM
Virta
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H
Simons
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K
Ikonen
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E
D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000032:analysis / Q000494:pharmacology; D001483:Base Sequence; D001692:Biological Transport; D051242:Caveolin 1; D022461:Caveolins; D002460:Cell Line / Q000737:chemistry; D002462:Cell Membrane / Q000737:chemistry / Q000648:ultrastructure; D003001:Cloning, Molecular; D003600:Cytosol / Q000737:chemistry / Q000648:ultrastructure; D018076:DNA, Complementary / Q000235:genetics; D005089:Exocytosis / Q000235:genetics / Q000502:physiology*; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000187:drug effects / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D008969:Molecular Sequence Data; D011108:Polymers; D011233:Precipitin Tests; D011506:Proteins / Q000737:chemistry; D012756:Sheep; D012995:Solubility
D000906:Antibodies; D051242:Caveolin 1; D022461:Caveolins; D018076:DNA, Complementary; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D008565:Membrane Proteins; D011108:Polymers; D011506:Proteins